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Keywords:

  • programmed cell death (PCD);
  • cold stress;
  • DNA ladder;
  • cucumber;
  • ethylene

Abstract

BACKGROUND

Cucumber fruit is susceptible to chilling injury (CI), which could be accelerated significantly with subsequent shelf-life. This type of CI culminates in deterioration of organs and eventually leads to cell death. In this study, evidence of programmed cell death (PCD), involving cell death induced by cold stress, was investigated in cucumber. Harvested cucumber (Cucumis sativus L. cv. Zhexiu-1) fruits were stored at 2 °C for 3, 6 or 9 days and subsequently transferred to 20 °C for 2 days.

RESULTS

Significant cell death acceleration was observed upon reconditioning after 9 days' cold stress when the hallmark of PCD – DNA laddering – was clearly observed. Further evidence of nuclear DNA cleavage was confirmed by the in situ TdT-mediated dUTP nick end labeling (TUNEL) assay. Chromatin condensation and nucleus distortion were observed by nuclear staining of DPI. Ethylene burst was observed upon reconditioning after 9 days of consecutive cold stress.

CONCLUSION

The features of PCD process induced by reconditioning after cold stress in cucumber fruit may be mainly attributed to ethylene burst. © 2013 Society of Chemical Industry